Elevator safety apparatus



June 13, 1950 Filed Dec. 12, 1947 rowan .SUPPLY W. C. CLIFT ELEVATOR SAFETY APPARATUS 2 Sheets-Sheet 1 INVENTOR.

LU/LL/Hm C. CLIFT June 13, 1950 w. c. CLlFT 2,511,697

ELEVATOR SAFETY APPARATUS Filed Dec. 12, 1947 2 Sheets-Sheet 2 20 az/b 2 27 27 28 2 3 25 Q 0/ 4 3/ '0 0 J' J! SF 0 4 24 /0 Q L INVENTOR.

LUlLL/H/T) C. CL/FT F1] La d 22 A 2M Patented June 13, 1950 UNITED STATES PATENT OFFICE ELEVATOR SAFETY APPARATUS William C. Clift, Philadelphia, Pa.

Application December 12, 1947, Serial No. 791,207

13 Claims. 1

cessive downward speed, the governor mechanism is actuated to grip and hold the governor cable and, because of the releasable connection, the car breaks loose from the cable and continues its downward movement relative thereto. This relative movement causes the safety device to move suitable clamping members into engagement with the elevator guide-rails and thereby to stop the movement of the car. Thus it is seen that successful operation of such elevator safety devices is dependent upon relative movement between the governor cable and. the car, otherwise it fails.

Upon occasion, it has happened that the hoisting cable has been severed-or otherwise rendered inoperable-simultaneously with the governor cable, with the consequence that the safety device was rendered ineffective to stop the car which dropped to the bottom of the hatchway, with disastrous results to its occupants.

The present invention has for its primary object to provide improved elevator safety apparatus operative, in response to dangerous operational conditions, positively to stop the car.

Still another object of the invention is the provision of elevator safety apparatus operable automatically in response to failure either of the elevator hoisting apparatus, the governor mechanism, or both simultaneously.

A further and more specific object of the inventi on is to provide elevator safety apparatus which is effective automatically to operate in response to predetermined excessive speed of the car, either in ascent or descent, to stop the movement thereof in a predetermined safe interval of time or distance.

.The manner in which the aforesaid, and other objects, are attained will become apparent from the following specification and the accompanying drawings illustrating a preferred embodiment of the'invention, andinwhich:

Figure l is a diagrammatic view of an eleva tor system embodying the present invention;

Figure 2 is a fragmentary bottom plan view of an elevator car showing safety apparatus mounted thereon;

Figure 3 is an elevational view on an enlarged scale of the governor mechanism, as viewed from the side opposite to that shown in Figure l; and

Figure 4 is a diagrammatic view of a modified form of the invention.

With reference to Figure l of the drawings, the numeral l0 identifies the elevator car which is raised and lowered by means of the hoisting cable I I having one end attached to the car, as at l2, and its other end connected to a suitable counterweight I3. The cable H extends over a traction sheave M, which is driven by a motor l5 of suitable capacity.

As shown in Figure 2, safety apparatus, indicated generally by the numeral 20, is mounted on the bottom 2| of car [0. This apparatus may be of any suitable type, but, for the purpose of simplificatiomthe present embodiment has been illustrated ascomprising the following described mechanism. A safety drum 22 is mounted for rotation upon a pair of shafts 23 which are oppositely threaded into the ends of the drum. Shafts 23 are journaled in supports 24 secured to the bottom of the car in any convenient manner, and have their outer ends pivotally connected to the knuckles of toggles 26. The ends 21 of the toggle links are pivotally connected to the clamping jaws 28 which, in turn, are pivotally secured to the bottom of the car, as at 29. The outer ends of these jaws normally move freely over stationary guide rails 3| positioned at each side of the elevator shaft on hatchway 32, but are adapted to be actuated, by rotation of the drum, into clamping engagement with the rails.

As illustrated, and in one mode of operation, drum 22 is rotated by means of a safety rope or cable 33 which has one of its ends wrapped around and fixed to the drum, and its other end extending over an idler pulley 34 and fixed to a governor cable 35, as at 36 (Figure 1). Governor cable 35 extends in a continuous path around upper and lower governor sheaves 31 and 38, respectively, and, as clearly seen in Figure 1, is releasably connected to the car by a suitable yieldable connection 42. This connection is sufllciently' secure to move the cable freely around sheaves 31 and 38 duringnormal operation of the car, but, under an extraordinary relative pull between cable 35- and the car, the cable will are oppositely positioned and have equal radial displacement from shaft 41, in order to balance the sheave 31 which is rotatably mounted on -a shaft 41, the latter being supported in anyssuitable manner, not shown. A rigid link 48 connects adjacent ends of the dogs so that-their radial displacement remains eq al. -;Dogs,,4 and 45 may be set to move outwardly at a rotational speed of sheave 31, which may be adjustablyip'nedetermined, as desired,gby tension means 49 poition d betwe n one end .tfl-pf wa h i an Ja r 5.! :9I 'h 1bf5' fif th sheave :T ten n meansmay hes hompris a breaded 2 abo whishas rins A P9 i 9; 'l n 'sfilldQ ih rod is pivotally secured to end of dogjfilgwhile 9 1 sad i shdahl repa red in an shat e (ac show i "9 space in! assiste hr u ss ther tsetisaph re diih h g a t si i of weights W 7 his as sn sit phs r aas t e Wei ht and of "can? r i lleah s 't e dses an A6 is .p Q- i sd t phi-er sad w th a I -i E lTQX -Wl iQP tt-w i h w n theaees s in hi warms hr snohs t xse s eed I the hae, s rike he u e an 33 lev r 6.2 whi h la ter is normall b ased toward the vertical position, illustrated, ,by springs 9i, shac hau t e right-s de ss-nsnq elhrelse hss ihhiehx 37th? sheave ro atin in glogkwi ir nfisusr vv62 moves he as ls thh h the Path 9 a tast n hih at 4 .lsrihi the d we 1 9 ahieh e shi n h t9.si vss esthea s ihq rops fi fip P11? hossrstihs EQFZQPQ 1 W. he 1113 W NK-E 9 :9 k P$ l P m m n Th h sva ls is" irsi l m hh "u st tishery st hsture i s-t l l9W. l 1 t 6 the g e r ab is s d i ti nued movement of the car creates the necessar rela ive i r m ht t a h he e id releasable connection and cause safety rope 33 to unwind from and rotate drum 22 "This rotation 'se rvesethrough shafts 23 and toggles'28- to'bring-the clamping jaws into engagemntwith rails 3-[ and thus to stop the downward movement oi the car.

Thus it isseen that-the safety apparatus, as set forth above, willstop the oar in' response to excessive downward speed thereof when-the ap paratus eis functioning in its intended manner. However, as :thus far described, the apparatus would not function if the governor cable :broke, or' for some other reason was rendered incapable of rotating drum -22. Therefore, in addition to thelabove described mechanism, and in particular. accordanceewith the presentinvention, means is provided for stopping'thelcariii-response to the existence .of any one of several such dangerous conditions, to bed scr be h r in fte -:Norma1 operation of the elevator, to raise ,or lower car .10, is contrqlled rom within thecar through suitable means, such a th rica circuits diagrammatically illustrated in Figure 1 iAsishown in -this figure;there is provided; a mans 44 and 4 5fisdetermined iby the stop ual control lever i5 positioned in the car and adapted selectively to close suitable circuits for operating a double pole magnetic switch i6 to energize hoist motor l5, and thus to raise or lower the car. With the control lever moved against stationary contact I7, solenoid 78 is energized to draw armature T9 of the switch to the left, as illustrated, and move switch arms 80 and 8| against stationary contacts 82 and 83, thereby closing "the power circuit through normally closed switches 84 and 85 and thus energizing the hoist motor to raise the car.

=Movement of the control switch or lever 15 r against stationary contact 85, energizes solenoid 81 to draw armature T9 to the right, as illustrated, moving the switch arms 80 and 8| against stationary contacts 153 and 88, respectively, thus closing the power circuit through switches 84 and at and energizing the hoist motor to lower the car.

EQ EQF 'raQ QI-Q PB B with the nre eh i vs tion, the -;safety apparatus 20, as illustrated igure .2 i .h s sl d t a diti a eans. esponsive to emergency conditions, described h rein te e a i ed m Z to o c ampihs Jews 23 i t ipp n n a e e with ails giL-as described above. This means includes a large gear 99 secured to the right end of the and in mesh with a driving pinion 9 l, which isadahte to ha h tsdh -lm t r .9 e u dby suitable means (notshown) to-the bottom of car 2|. Motor @2 15 normally inoperative but may he placed circuit with the power supply, by ,clo- Sureof the np ina ly open switches shown at.93 ahsirfl wits 3 a il ust t i i ur 1, i ps tithes-bel sw t h nd bo a dap ed it; beactuated by a switch actuating .arm, showndiagrammatically at ,95, in response to excessive l wer-ing pi sheave .33 as would occur in the eyent cable-35 was severed and collapsed into the hatchway. .It should be understood, however, th t actuation of ,these switches is not reflected bysnorma sth tshih h g ve n r e 3.5- h s swi hhes $93 an harrov m hsl h breaking th ni e? sh ly to t hoi in m t r nd at the same time, energizing safety'motor 92 wherebyte rotate-d am 22 and s the car. a d $i $$1 ab i t e e en vern c b 5 is e e edhi -hast s en in F u 3 w ch 8.4 o th h is m to P Wfi up l h r tl nd swi h .93 0f t e safetyrnotor power supply circuit, are adapted to be uat d by ve hh in 'BSPQDS BXr cessive r ta i na s e d thereo i ei .d h i h an the ew h reak th hoi mo or sh t hhhl s ash the safety mo o C uit. The mechanism for so-actuating these switches con h i s a amme act at n a m d ag mma can rsn esshtsd t 6, nd en ionor fin er 9 F PQhS n8 i m lever 52,-

l varioiish h h un er w h t afety mechanism is particularlyrefiective and theman- .ih hi hth ap ar tus ,o h i enti cp sr tss, un er such ond t o s. w now e .dess ed- F rsh mi h s ch s an xcess u a d st ed, the e rhqr m ch sm w l o e a to thr w 9 the weight d end o do s 44 a d 45 which strike lever 62 on the left side, as seen Ei hts =3 h pi ot g fing 9,1 in a clockw direction to open the power circuit to the hoist motor (through switch 34) andclosing thesafety mot r irshi simu a u n thi manner safety motor 92 is energized, which moton in tiirrfjn'ioves clamping jaws 28 into gripp ng engagei nent with rails 3|, and thereby prevents the car-crashing into the floor IO'I-of the control room at' -the top of the hatchway. It is to be noted that, when the car is moving upwardly at'such an excessive speed, movable grippingjaws 66 are hoistmotor I5 is opened and the circuit to safety motor 92 is closed, thus assuring positive operation of the safety apparatus, both through safety rope 33 and motor 92. v

Other emergency conditions in which the apparatus is particularly effective arise when either the governorcable or the hoist cable become severed, in which event the safety apparatus will operate in the manner described hereinafter.

for example, the hoist cable breaks, the car falls freely and almost immediately reaches the speed necessary to actuate the governor mechanism to grip the associated cable and break the yie'ldable connection between the car and cable thus causing the relative movement between the car'and cable necessary to actuate the safety mechanism and stop the fall of the car. Simultaneou'sly with the foregoing, and as above described, the'governor mechanism opens switch 84 breaking-the circuit to the hoist motor l5 and closes switch 93, to energize safety motor 92 and actuate the safety apparatus as described above. By providing two actuating means, capable of acting either simultaneously or individually, the safety apparatus, of the invention completely eliminates the possibility of the car falling be cause of failure of the safety rope 33.

If the governor cable alone is severed or broken,

lower'governor sheave 38 drops or collapsesinto th'e hatchway opening the power circuit'tojthe hoist motor, as a result of arm 95 bearing against switch 84, and simultaneously closing the circuit to the safety motor through the agency of switch 94, and thus actuating the safety apparatus. Thus, it may be seen that, even though both the hoist cable and the governor cable be severed, the safet apparatus will operate to stop the car safely and maintain it stationary.

After such actuation of the governor mechanism as serves to release the movable gripping jaw 66, the mechanism may easily be reset by pressing downwardly on the lateral extension 98 of jaw 56 until pin 64 is reengaged under the finger 99 of lever 62.

From the foregoing description, it will be evident that the present invention provides a safety apparatus operable under virtually every dangerous operating condition which might be encountered. However, in some installations where the danger of power shut-off is present, it is additionally proposed to replace the power actuated motor 92 with a spring actuated device, as shown in the modified form of the invention illustrated in Figure 4.

As shown in this figure, the apparatus includes drum 22, gear 96 and pinion 9|, as heretofore described. In this form, however, the pinion is adapted to be driven by a spring motor device comprising a coil spring I00, which is preloaded bymeans of a rack and pinion l0! and I02, respectively. The rack is directly connected to the armature I03 of a solenoid I04, which, when energized, urges the rack to an advanced position in which the pinion I02 has been rotated to load the spring and hold the safet apparatus in its inoperative position, that is, in such position that clamping jaws 28 are free to slide over guide rails 3! 'A spring I05, having one end reacting against fixed structure I06, may be provided to assist the solenoid I 05 in preloading spring I00. If for any reason the power should fail, solenoid I04 is deenergized releasing the spring I00, which then serves to rotate the pinion and gear, and thereby to actuate the safety mechanism in the manner described heretofore with relation to the preferred form.

It will be seen, therefore, that my invention provides improved safety apparatus for elevator cars;

which is highly effective and, further, positively protects against mechanical failures not hithertoprovided for.

" I claim: i

l 1. In safety apparatus for elevator cars operable upwardly and downwardly within a hatchway, a safety device carried by the car, said device including a rotatable drum and means actuated b rotation of said drum for gripping fixed hatchway structure thus to stop the car, governor means including a governor cable releasably connected to said car and having means adapted when said cable is released from said car to rotate said drum so to actuate said gripping means, and electro-mechanical means cooperable with said governor means to rotate said drum to stop the car.

ZLSafety apparatus for elevator cars comprising a safety mechanism for stopping the car, governor means responsive to a predetermined down-ward speed of said car and including a cable effective to actuate said safety mechanism, and electro-mechanical means effective to actuate said safety apparatus in response to failure of said cable.

3. Apparatus in accordance with claim 2, and

further characterized in that said cable is ar-.

ranged parallel to the path of car travel and operatively associated with said safety mechanism,

and in which said electro-mechanical means is responsive to severing and consequent collapse of said cable.

4. The combination with an elevator system comprising an elevator car, a safety device including a drum and operable by rotation of said drum, a safety cable reeled upon said drum, and governor means responsive to predetermined speeds of the elevator car to cause said safety cable to unreel from said drum to actuate said safety device and thereby to stop the car; of electro-mechanical means associated with said governor means and operable conjointly with or independently of said safety cable and in response to a predetermined speed of said car to rotate said drum and thus operate said safety device.

5. A construction in accordance with claim 4 and including means responsive to collapse of said safety cable to energize said electro-mechanical means and thus to actuate the safety device.

6. The combination with an elevator system comprising an elevator car, a safety device including a drum and operable by rotation of said drum, a safety cable reeled upon said drum, and governor means responsive to predetermined speeds of the elevator car to cause said safety ZWILBQW cableto'unreel from said drum' to actuate-said safety device and thereby to stop the car; of electro-mechanical means associated with said governor means and operable conjointly with or independently of said safety cable and in response to a predetermined speed of said car to effect operation of said safety device, and means for energizing said electro-mechanical means in response to execessive upward speed of said car to actuate the safety device independently of said safety cable.

Y 7. Safety apparatus for elevator cars comprising' a safety device for stopping the car, governor means, means connecting said governor means with-said safety device, said governor means being responsive to a predetermined downward speed of said car to cause said connecting means to actuate said safety mechanism, electromechanical means responsive to a predetermined downward speed to operate conjointly with said connecting means and said safety mechanism to stop the car, said governor means being operable in response to a predetermined upward speed of said car to actuate said electro-mechanic'al means to stop the car, and means responsive to severing of said connecting means to effect opei-- ation' of said electro-mechanical means and thus to actuate said safety apparatus.

8. In combination with an elevator car, hoistmg means for moving said car up and down a hatchway, a safety mechanism carried by the cansaid safety mechanism including a drum rotatable to actuate clamping means against fixed hatchwa'y structure, a safety cable wound on said drum, speed responsive governor mechanism, a

governor cable releasably secured to said car and so attached to said safety cable as to operate said speed responsive mechanism at speeds corresponding to the speed of the car, means responsive to a predetermined speed of said car to grip and hold said governor cable whereby continued movement of the car is effective to cause rotation of said safety drum to stop the car, electro mechanical means for rotating said drum, normally open switch means adapted, when closed, to energize said electro-mechanical means, and means responsive to collapse of said governor cable to' close said switch means.

9. A construction in accordance with claim 8-. and wherein said switch means is also adapted to render said hoisting means inoperative.

i mechanical means responsive to power cut-off to rotate said member.

11. In an elevator system of the type having a-car, a safety mechanism for stopping the can and a governor cable, and in which relative movement between said car and cable is effective tooperate said safety mechanism, the improvement which comprises: means for effecting operation ofsaid safety mechanism, said means being responsive to severing and consequent collapse of" saidgovernor cable.

12; In an elevator system of the type having or car, a safety mechanism for stopping the-carand" a governor cable, and in which relative movement between said' car and cable is effective'tof operate-said safety mechanism, the improvement which comprises: means for effecting operation of said safety'mechanism, said means comprising anelectro-mechanical actuator responsiveto severing and consequent collapse-of said-governor cable.

13. In an elevator system of the type havinga car, a safety mechanism for stopping the car and a governor cable, and in which relative move ment between said car and cable is effective to operate said safety mechanism, the improvement which comprises: means for effecting operation of said safety mechanism, said means comprising" an electrical device adapted to! actuate said safety mechanism, and switch means adaptedtof energize said electrical device and so positioned with respect to said governor cable'asto be responsive to severing and consequent collapse of the latter.

WILLIAM C. CLIF'I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITET) s'rATEs PATENTS 

